1. Field of the Invention
The present invention relates to a lamp holder structure for lamp of Christmas light string, and more particularly relates to a lamp socket device configured with special fitting hole for fitting of a twinkle light bulb.
2. Description of the Prior Art
A prior art Christmas light string is comprised of a series of regular lamps which are electrically connected to an electric power source via two wires. FIG. 1 is the exploded view showing a prior art lamp 1 is mounted on a lamp base 2, and then received in a fitting hole 31 of a regular lamp holder 3. The lamp 1 includes two conductive wires 11, 12 which are extended from the bottom end of the lamp base 2. The regular lamp holder 3 includes a circular top open end. Two metal plates are embedded in the corresponding inner wall of the lamp holder 3, which are respectively connected with two conductive wire 41, 42 for connection to the light string. The lamp 1 with the lamp base 2 is mounted into the fitting hole 31 of the lamp holder 5.
To create flashing effect, at least one flashing lamp is electrically connected with a series of regular lamps. Conventionally, a flashing lamp includes two conductive poles which are connected with exterior conductive wires. A bimetal plate is connected between two ends of the conductive poles. When the conductive poles are supplied with an electric power source, the bimetal plate is heated. After a predetermined time is reached, the heated bimetal plate bends. The connection between the two conductive poles and hence the electric current flow through the conductive poles are cut off. Subsequently, the lamp is not heated and is cooled down. After the lamp has cooled to a predetermined temperature, the bimetal plate will return to the original state and connection between the two conductive poles is restored. Thereby, the illumination of the light string is controlled by the heating state of the bimetal plate in the flashing lamp.
However, this prior art Christmas light string only provide a monotonous flashing effect. Although a plurality of light strings can be connected in parallel to enhance the flashing effect, the flicking patterns are limited and monotonous.
In another prior art, a plurality of light strings are connected in parallel, each of which comprises an appropriate number of twinkle lamps connecting to a series of regular lamps. By means of the twinkle lamps, various flickering patterns are created.
Anyway, in designing the parallelly connected bulb strings, designer should be cautious of the number of twinkle lamps used. Improper design of using too many twinkle lamps may cause overloading of electricity to regular lamps which may burn at the instant of flashing of the twinkle lamps. Such a catastrophe also happens when twinkle lamp is mistakenly mounted to the lamp holder of regular lamp.
Therefore, it is necessary to provide a lamp socket device with fitting hole particularly configured for Christmas flashing lamp which processes corresponding configuration for fitting into the fitting hole. By this mean, it is not able to fit the Christmas flashing lamp into the lamp holder for regular lamp.